Nuclear ß-catenin translocation plays a key role in osteoblast differentiation of giant cell tumor of bone.

Denosumab is a game-changing drug for giant cell tumor of bone (GCTB); however, its clinical biomarker regarding tumor ossification of GCTB has not been elucidated. In this study, we investigated the relationship between Wnt/ß-catenin signaling and the ossification of GCTB and evaluated whether endogenous nuclear ß-catenin expression predicted denosumab-induced bone formation in GCTB. Genuine patient-derived primary GCTB tumor stromal cells exhibited osteoblastic characteristics. Identified osteoblastic markers and nuclear ß-catenin translocation were significantly upregulated via differentiation induction and were inhibited by treating with Wnt signaling inhibitor, GGTI-286, or selective Rac1-LEF inhibitor, NSC23766. Furthermore, we reviewed the endogenous ossification and nuclear ß-catenin translocation of 86 GCTB clinical samples and elucidated that intra-tumoral ossification was significantly associated with the nuclear translocation. Three-dimensional quantitative analyses (n = 13) of tumoral CT images have revealed that the nuclear ß-catenin translocation of naïve GCTB samples was significantly involved with the denosumab-induced tumor ossification. Our findings suggest a close relationship between the nuclear ß-catenin translocation and the osteoblastic differentiation of GCTB. Investigations of the nuclear ß-catenin in naïve GCTB samples may provide a promising biomarker for predicting the ossification of GCTB following denosumab treatment.

Methylation-mediated silencing of protein kinase C zeta induces apoptosis avoidance through ATM/CHK2 inactivation in dedifferentiated chondrosarcoma.

BACKGROUND: Dedifferentiated chondrosarcoma (DDCS) is an aggressive bone tumour with a poor prognosis and no effective treatment. Because changes in DNA methylation play critical roles in DDCS, we explored the roles that DNA methylation plays in oncogenesis to potentially identify an effective epigenetic treatment. METHODS: We identified genes downregulated in DDCS vs. conventional chondrosarcoma (CCS) due to DNA methylation using in silico analysis. The results were validated in DDCS clinical samples, and the molecular functions of the genes of interest were investigated in multiple chondrosarcoma cell lines (NDCS-1, SW1353, and OUMS-27). The therapeutic effect of decitabine, a DNA methyltransferase inhibitor, was evaluated in vitro and in vivo. RESULTS: PRKCZ was specifically downregulated by DNA methylation in DDCS. Overexpression of PRKCZ decreased the proliferation of NDCS-1 and SW1353 cells. PRKCZ directly bound to and activated ATM, which was followed by phosphorylation of CHK2 and subsequent apoptosis. Decitabine increased PRKCZ expression through de-methylating the promoter region of PRKCZ, which activated the ATM/CHK2 pathway and inhibited cell proliferation by inducing apoptosis. CONCLUSIONS: Increased DNA methylation and reduced expression of PRKCZ prevents apoptosis via inactivation of the ATM/CHK2 pathway in DDCS. Decitabine-induced expression of PRKCZ represents a promising therapy for DDCS.

Clinical benefits of vessel sealing system (LigaSure™) during surgery for soft tissue sarcoma: a propensity score matching analysis.

BACKGROUND: Soft tissue sarcomas arise in the deep sites of the buttocks and lower extremities. Since a tourniquet is not applied during surgery for soft tissue sarcomas at such sites, excessive intraoperative blood loss may occur. Various devices, including LigaSure™ (Medtronic, Dublin, Ireland), are used as electrothermal bipolar vessel sealers. However, its clinical relevance in soft tissue sarcomas surgery remains unclear. This study aimed to assess the effectiveness of LigaSure™ in soft tissue sarcomas surgery. METHODS: This study included 168 patients who underwent surgeries for soft tissue sarcomas in the deep sites in the buttocks and lower extremities between January 2004 and March 2018. The primary outcome was intraoperative blood loss, and secondary outcomes were surgery duration, wound complications, perioperative haemoglobin concentrations and intraoperative blood transfusion. To reduce selection biases, propensity score matching was applied. We defined the matched cases wherein LigaSure™ was used as the 'using group' and the other matched cases as the 'non-using group'. Outcomes were compared between both groups. RESULTS: From each group, 35 cases were selected using propensity score matching. The intraoperative blood loss was significantly smaller statistically in the using group (181.5 ± 240.4 ml vs. 394.7 ± 547.3 ml, respectively; P = 0.041). The duration of operation was longer in the using group (189.9 ± 97.6 min vs. 140.6 ± 75.7 min, respectively; P = 0.007). There were no significant differences in other outcomes. CONCLUSION: By using LigaSure™ for soft tissue sarcomas occurring in the buttocks and lower extremities, we observed a trade-off between reduced intraoperative blood loss and longer operative time.

Immunotherapy for osteosarcoma.

Osteosarcoma (OS) is the most common malignant bone tumor and often occurs in children. Chemotherapy with methotrexate, cisplatin, doxorubicin, and ifosfamide has greatly improved the prognosis of patients with OS, and most patients have been able to preserve their limbs. However, no progress has been made in the treatment for OS in the past few decades, and the prognosis of patients with metastasis and/or local recurrence remains poor. Therefore, studies aimed at developing new treatment methods for OS are urgently required. Here, we discuss the current status of immunotherapies for OS as well as the current limitations in the field.In recent years, immunotherapy has been shown to be effective for treating several cancers, and its indication is continually increasing. Immunotherapy is also expected to be widely used for treating OS, however, the efficacy of immunotherapy for OS has not been established.

Activation of TLR4 signaling inhibits progression of osteosarcoma by stimulating CD8-positive cytotoxic lymphocytes.

BACKGROUND: Osteosarcoma (OS) is the most common malignant bone tumor and the prognosis of advanced cases is still poor. Recently, there have been several reports suggesting the relationship between innate immunity and OS, but the detailed mechanism is unknown. We demonstrate the relationship between OS and Toll-like receptor 4 (TLR4) which is one of the most important factors in innate immunity. METHODS: We established a syngenic mouse tumor model using C3H/HeN, C3H/HeJ mouse and a highly metastatic OS cell line, LM8. TLR4 activation with lipopolysaccharide (LPS) was performed on both mice and its influence on the progression of OS was evaluated. We also performed CD8 + cells depletion to examine the influence on TLR4 activation effects. RESULTS: Tumor volume of C3H/HeN mice was significantly smaller and overall survival of C3H/HeN mice was significantly longer than C3H/HeJ mice. We found more CD8+ cells infiltrating in lung metastases of C3H/HeN mice and depletion of CD8+ cells canceled the antitumor effects of LPS. CONCLUSION: TLR4 activation by LPS increased CD8+ cells infiltrating into lung metastases and suppressed OS progression in the mouse model. TLR4 activation may suppress the progression of OS via stimulating CD8+ cells and can be expected as a novel treatment for OS.

Selective inhibition of mutant IDH1 by DS-1001b ameliorates aberrant histone modifications and impairs tumor activity in chondrosarcoma.

Chondrosarcoma is the second most common malignant bone tumor. It is characterized by low vascularity and an abundant extracellular matrix, which confer these tumors resistance to chemotherapy and radiotherapy. There are currently no effective treatment options for relapsed or dedifferentiated chondrosarcoma, and new targeted therapies need to be identified. Isocitrate dehydrogenase (IDH) mutations, which are detected in ~50% of chondrosarcoma patients, contribute to malignant transformation by catalyzing the production of 2-hydroxyglutarate (2-HG), a competitive inhibitor of α-ketoglutarate-dependent dioxygenases. Mutant IDH inhibitors are therefore potential novel anticancer drugs in IDH mutant tumors. Here, we examined the efficacy of the inhibition of mutant IDH1 as an antitumor approach in chondrosarcoma cells in vitro and in vivo, and investigated the association between the IDH mutation and chondrosarcoma cells. DS-1001b, a novel, orally bioavailable, selective mutant IDH1 inhibitor, impaired the proliferation of chondrosarcoma cells with IDH1 mutations in vitro and in vivo, and decreased 2-HG levels. RNA-seq analysis showed that inhibition of mutant IDH1 promoted chondrocyte differentiation in the conventional chondrosarcoma L835 cell line and caused cell cycle arrest in the dedifferentiated JJ012 cell line. Mutant IDH1-mediated modulation of SOX9 and CDKN1C expression regulated chondrosarcoma tumor progression, and DS-1001b upregulated the expression of these genes via a common mechanism involving the demethylation of H3K9me3. DS-1001b treatment reversed the epigenetic changes caused by aberrant histone modifications. The present data strongly suggest that inhibition of mutant IDH1 is a promising therapeutic approach in chondrosarcoma, particularly for the treatment of relapsed or dedifferentiated chondrosarcoma.

Diagnosis and Management of Subcutaneous Soft Tissue Sarcoma.

OPINION STATEMENT: The proper diagnosis and treatment planning for subcutaneous soft tissue sarcoma is very important. Soft tissue tumors can occur anywhere in the body, but if they occur subcutaneously, patients can easily notice a subcutaneous soft tissue mass. Therefore, it is possible to determine through recording, the growth speed of the mass, which is often difficult to obtain with deep-situated soft tissue masses. Palpation can also provide information about the firmness and mobility of the mass. Thus, history taking and physical examinations are informative for subcutaneous soft tissue tumors, compared to tumors that occur deeply. Because subcutaneous soft tissue tumors are easily recognized, they are often resected, without sufficient imaging analyses or thorough treatment planning. An operation performed based on such an inadequate preoperative plan is called a "whoops surgery." In the case of "whoops surgeries," subsequent radical surgery is required to remove additional areas, including hematomas that result from the initial surgery, that require a wider range of resection and soft tissue reconstruction. Therefore, as with deep-seated soft tissue tumors, it is important to conduct careful imaging examinations and make appropriate preoperative plans for subcutaneous soft tissue tumors. Subcutaneous soft tissue sarcomas often show an invasive pattern, and such tumors require a more careful assessment to prevent local recurrence after surgery. During surgery, it is necessary to remove the entire infiltration area along the fascia. Sometimes, an adequately wide excision is necessary, which is considered the minimum necessary procedure to eradicate the lesion. As noted above, clinicians who see patients with subcutaneous soft tissue tumors are encouraged to have sufficient knowledge and experience regarding the diagnosis and treatment. This article is intended for all doctors who deal with subcutaneous soft tissue tumors and focuses on essential points regarding their diagnosis and management.

Class III ß-Tubulin Overexpression Induces Chemoresistance to Eribulin in a Leiomyosarcoma Cell Line.

Eribulin is a new drug to treat soft tissue sarcoma (STS) that exerts antitumor activity by binding to microtubules. The prognosis of STS is poor, and eribulin is expected to improve the treatment outcome. We observed several cases that exhibited resistance to eribulin and developed an eribulin-resistant leiomyosarcoma cell line to investigate the mechanism of resistance. The IC50 of eribulin was 125 times higher in the resistant cell line than in the parental cell line, and eribulin did not induce G2/M arrest in resistant cells. The resistant cell line showed increased expression of MDR1 transcript, but protein levels and functional analysis results were similar to the parental cell line. We found that class III ß-tubulin (TUBB3) was overexpressed in the resistant cell line, and siRNA knockdown of TUBB3 partially recovered sensitivity to eribulin. TUBB3 expression in clinical samples varied, suggesting that TUBB3 has the potential to be a biomarker for selection of anticancer drugs and may be a target for overcoming resistance to eribulin.

Correction: Hypoxia-inducible factor 1 alpha is a poor prognostic factor and potential therapeutic target in malignant peripheral nerve sheath tumor.

[This corrects the article DOI: 10.1371/journal.pone.0178064.].

Hypoxia-inducible factor 1 alpha is a poor prognostic factor and potential therapeutic target in malignant peripheral nerve sheath tumor.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. Hypoxia-inducible factor 1 (HIF-1) plays a crucial role in the cellular response to hypoxia and regulates the expression of multiple genes involved in tumor progression in various cancers. However, the importance of the expression of HIF-1α in MPNSTs is unclear. METHODS: The expression of HIF-1α was examined immunohistochemically in 82 MPNST specimens. Cell culture assays of human MPNST cells under normoxic and hypoxic conditions were used to evaluate the impact of anti-HIF-1α-specific siRNA inhibition on cell survival. A screening kit was employed to identify small molecules that inhibited HIF-1α. RESULTS: The nuclear expression of HIF-1α was positive in 75.6% of MPNST samples (62/82 cases). Positivity for HIF-1α was a significant poor prognostic factor both in univariate (P = 0.048) and multivariate (P ≤ 0.0001) analyses. HIF-1α knockdown abrogated MPNST cell growth, inducing apoptosis. Finally, chetomin, an inhibitor of HIF-1α, effectively inhibited the growth of MPNST cells and induced their apoptosis. CONCLUSION: Inhibition of HIF-1α signaling is a potential treatment option for MPNSTs.

Incidence and risk factors of calcaneal enthesophytes in spondyloarthritis and trauma patients.

OBJECTIVE: Achilles enthesitis and plantar fasciitis are the features of spondyloarthritis (SpA). Enthesophytes may indicate enthesitis, but their incidence is also high in elderly individuals and in athletes. This study aimed to clarify the incidences and risk factors of Achilles enthesophyte (AE) and plantar entesophye (PE) in SpA and trauma patients. METHOD: We retrospectively surveyed radiographs of the feet of SpA and trauma patients in our hospital. The SpA group included 17 patients (33 feet), and the trauma group included 33 patients (37 feet) who had undergone surgery between April 2013 and March 2014. RESULTS: The incidence of AEs was 63.6% (21 feet) in the SpA group and 54.1% (20 feet) in the trauma group (p = 0.45). The incidence of PEs was 48.9% (16 feet) in the SpA group and 16.2% (6 feet) in the trauma group. The SpA group had a higher prevalence of PEs than the trauma group (p < 0.01). The multivariate analysis showed that the risk factors for AEs and PEs were SpA and age. CONCLUSION: The risk factors for AEs and PEs were found to be advanced age and the presence of SpA.